Factivity, hallucination, and justification

Abstract

Veridically perceiving puts us in a better epistemic position than, say, hallucinating does, at least in that veridical perception affords knowledge of our environment in a way that hallucination does not. But is there any further epistemic advantage? Some authors have recently argued that veridical perception provides a superior epistemic benefit over hallucination not just concerning knowledge, but concerning justification as well. This contrasts with a traditional view according to which experience provides justification irrespective of whether it’s veridical or hallucinatory. I think both views are mistaken. Although this traditional view should be rejected in favor of one on which some hallucinations are epistemically worse than veridical perceptions (and some are not), I don’t believe there is good reason to think that the mere fact of hallucination—or factivity more generally—has any consequences for justification. Susanna Schellenberg has endorsed both the traditional and the factive views (for different elements or kinds of perceptual justification), and I critique her views in detail, though I also draw out more general epistemological lessons about factivity and evidence.